Method for producing a pack for groups of products and machine for implementing said method

ABSTRACT

A method for producing a pack ( 1 ) for groups ( 2 ) of rolls of products comprises the following steps: forming of a tube of film ( 3 ) around a frame ( 5 ) forming a channel ( 6 ) for the passage of the product groups ( 2 ); creation of a first seal (S 1 ) on the front edges ( 7 ) of the film ( 3 ); insertion in the channel ( 6 ) of product groups ( 2 ), fed until they are close to the closed front end ( 7 ) of the film ( 3 ); further feeding of the product groups ( 2 ) with simultaneous feeding of the film ( 3 ) and formation of the further portion of the pack ( 1 ) beyond the frame ( 5 ); creation of a second, longitudinal seal (S 2 ) on the overlapping longitudinal edges of the film ( 3 ) simultaneously with the further feed step; creation of a third seal (S 3 ) on the rear edges ( 11 ) of the film ( 3 ) designed to close the pack ( 1 ) at the rear of the product groups ( 2 ) bagged; between the step of insertion of product groups ( 2 ) in the channel ( 6 ) and the further feeding of the product groups ( 2 ), there being a step of feeding the film ( 3 ) wound around the frame ( 5 ), simultaneously with and in the same direction as the feeding of the product groups ( 2 ), designed to allow a fixed distance (D) to be maintained between the closed front end ( 7 ) of the film ( 3 ) and the front end ( 2   a ) of the product groups ( 2 ) fed forward.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 11/641,329filed Dec. 19, 2006, which claims priority from and benefit of thefiling date of Italian Application No. BO 2005A 000774 filed Dec. 20,2005, and the disclosure of said prior application Ser. No. 11/641,329is hereby expressly incorporated by reference into the presentspecification.

BACKGROUND OF THE INVENTION

The present invention relates to a method for producing a pack forgroups of products and to a machine for implementing said method, inparticular, but without limiting the scope of the invention, for kitchenand/or toilet rolls.

In particular, this text focuses on bagging machines normally used foroverwrapping a predetermined number of groups of products alreadypackaged in plastic film, although this does not limit the scope of theinvention, since the groups of products may also be pluralities orbatches of loose products.

These groups of products are grouped together in predetermined batchconfigurations then fed, one after another, into a tubular packagingfilm wrapper.

These bagging machines, which usually form a final station of machinesfor producing the above-mentioned groups of products, bag the groups ofproducts in tubular wrappers automatically formed by the bagging machineon the products to be overwrapped.

In practice, the machine forms the wrapper starting with a flat strip ofpackaging material film (fed from a reel positioned below a surface formovement of the groups of products). The strip of film is graduallyfolded over itself by special folder elements, forming a tube, supportedfrom the inside of the wrapper being formed by suitable supportingelements (so that it forms a “tunnel” with a quadrangularcross-section), and having the longitudinal edges drawn near andoverlapping one another.

There are also first sealing means positioned in front of the wrapperand the folder elements, angled transversally to the tubular shape,which then allow the wrapper to be sealed transversally to form, insequence, a closed front end and a closed rear end.

Finally, second sealing means, angled longitudinally to the wrapper andopposite the longitudinal edges, close the tubular wrapperlongitudinally to completely close the overwrap.

Basically, the process for forming the overwrap on the groups ofproducts comprises the following steps:

forming the overwrap with the film around the folders and the supportingelements;

first seal at the front of the overwrap film;

insertion in the channel formed by the folders of a predetermined numberof product groups, until they make contact with the closed front end ofthe wrapper;

further feeding of the product groups beyond the transversal sealers,simultaneously feeding the film from the reel thanks to the pushingmotion of the products, and formation of the overwrap, gradually as theclosed front end is fed along the machine together with the productsinserted;

simultaneously with the formation of the overwrap the overlapping edgesof film are longitudinally sealed by the second sealing means;

further activation of the first, transversal sealing means designed toclose the overwrap wrapper at the rear of the products already bagged;

cutting to separate the bag obtained in this way from the rest of thefilm, using cutting means, thus starting a new and subsequent baggingcycle for the product groups.

However, the machine structured in this way and the related operatingcycle have disadvantages due to:

rather lengthy times required for overwrapping which, at present, setsan operating limit for all of the stations upstream of the baggingmachine, which, over time, have been improved in terms of productquality and operating times; and

relatively low strength of the front seal at the current operatingspeeds.

In particular, on the current bagging machine the point on which suchproblems are focused is the sealing speed, in particular on the fronttransversal sealing speed.

The film sealing is a time T divided into two separate operatingsub-times, that is to say, the film melting time T1 and the seal coolingtime T2: where the time T1 for melting the material is relatively low,whilst the cooling time T2 is relatively long, since the quality andstrength of the seal is increased only after cooling.

Consequently, with the current cycle and with a transversal sealer fixedin a position, the front sealing times have to be observed in order toprevent the overwrap from breaking above all when the product groups fedforward come into contact with the front seal. As already indicated,product feed results in subsequent development of the overwrap.

SUMMARY OF THE INVENTION

The aim of the present invention is therefore to overcome theabove-mentioned disadvantages with a method and relative machine forproducing a pack or overwrap for product groups which are highlyproductive in the unit of time and provide an end product with goodstrength and quality.

Accordingly, the present invention achieves this aim with a method forproducing packs for groups of roll products, in particular a method anda machine for bagging groups of products with the technical featuresdescribed in one or more of the claims herein

BRIEF DESCRIPTION OF THE DRAWINGS

The technical features of the invention, with reference to the aboveaims, are clearly described in the claims below and its advantages aremore apparent from the detailed description which follows, withreference to the accompanying drawings which illustrate a preferredembodiment of the invention provided merely by way of example withoutrestricting the scope of the inventive concept, and in which:

FIG. 1 is a perspective view of a wrapper obtained using the method andmachine in accordance with the present invention;

FIG. 2 is a perspective view with some parts cut away to betterillustrate others, of the machine implementing the method for packaginggroups of roll products in accordance with the present invention;

FIGS. 3 to 8 are schematic side views with some parts cut away to betterillustrate others, of a succession of steps in the packaging methoddisclosed;

FIG. 9 is a side view with some parts cut away to better illustrateothers, of the bagging machine of FIG. 2;

FIG. 10 is a front view with some parts cut away to better illustrateothers, of the bagging machine of FIG. 2;

FIG. 11 is an enlarged front view of a first detail of the baggingmachine of FIG. 10;

FIG. 12 is a schematic top plan view with some parts cut away to betterillustrate others, of a detail of lateral feed belts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the accompanying drawings, and in particular withreference to FIGS. 1 to 8, the method and machine in accordance with theinvention are used to obtain a pack or wrapper—bag 1 of groups 2 of rollproducts, in particular, but without limiting the scope of theinvention, for kitchen and/or toilet rolls.

In this text reference is made to a process for bagging product groups 2already packaged in film and grouped into batches, although this doesnot limit the solution which may also be used for groups of looseproducts to be bagged with a sheet of film.

The method disclosed comprises the following steps (see FIGS. 1 to 8):

forming of a continuous tube of film 3 around supporting and foldermeans 4 which constitute a frame 5 forming a channel 6 for the passageof the product groups 2 (see FIG. 2);

creation of a first seal S1 on the front 7 edges of the packaging film3, using first, transversal sealing means 8 positioned close to thefront end of the frame 5 (see also FIG. 3 arrow F8);

insertion in the channel 6, by pusher means 9, of a predetermined numberof product groups 2, fed until they are close to the closed front end 7of the film 3 (see FIG. 4 arrow F9);

further feeding of the product groups 2 beyond the first sealing means8, with simultaneous feeding of the film 3 and formation of the furtherportion of the pack 1 beyond the frame 5 (see FIG. 6);

creation of a second, longitudinal seal S2 on the overlappinglongitudinal edges of the film 3, by second sealing means 10,simultaneously with the further feed step;

creation of a third seal S3 on the rear edges 11 of the film 3, by thefirst, transversal sealing means 8, designed to close the pack 1 at therear of the product groups 2 bagged (see FIG. 8 arrow F8 a).

FIGS. 4 to 6 show how, between the step of inserting product groups 2 inthe channel 6 (FIGS. 3 and 4) and the further feeding of said productgroups 2 (FIGS. 5 and 6), there is a step of feeding the film 3 woundaround the frame 5 (see arrows F14 in FIGS. 4 to 6), simultaneously inthe same direction as the product groups 2, designed to allow a fixeddistance D to be maintained between the closed front end 7 of the film 3and the front end 2 a of the product groups 2 fed forward: this is alldone by feed means 14.

This film 3 feed step may be continued at least until the product groups2 exit the channel 6, or in any event until the product groups 2 arepositioned beyond the first, transversal sealing means 8.

Alternatively, the film 3 feed step may continue at least until thefirst seal S1 on the front edges 7 of the film 3 has cooled.

FIG. 4 shows how the film 3 feed step begins at and simultaneously witharrival of the product groups 2 close to the front end of the frame 5and this feed step is performed evenly along the entire perimeter of thefilm 3 formed by the channel 6.

As illustrated in FIG. 7, before said step for creation of a third sealS3 on the rear edges 11 of the film 3, there may be a further step offeeding the product groups 2 until the product groups 2 make contactwith the front end 7 of the film 3, by the pusher means 9, to reduce orcompletely eliminate the distance D.

As illustrated in FIGS. 1 and from 9 to 11, the bagging machine 100 forproducing the pack 1 for product groups 2 described above basicallycomprises:

a surface 12 for supporting the product groups 2, extendinghorizontally, formed by an elevator (of the known type) designed toallow positioning of the product groups 2 on the operating line of thepusher means 9 before production of the pack 1;

the frame 5 consisting of the folder means 4 designed to support thepackaging film 3, which is wound around the folder means 4 and can befed from a station 13 (for example a reel positioned below the frame 5);the frame 5, as said, forms the channel 6 for the passage of the productgroups 2 fed, by the pusher means 9, in a direction of feed A and alongthe elevator 12;

the first, transversal sealing means 8 (consisting of two sealing bars)positioned downstream of the frame 5, relative to the direction of feedA, and designed to join, respectively, the front edges 7 of thepackaging film 3, before arrival of the product groups 2, and the rearedges 11 after the product groups 2 wrapped in the packaging film 3 havepassed beyond the first sealing means 8;

the second, longitudinal sealing means 10, positioned close to the frame5 (for example above the frame 5), and designed to join two longitudinaledges of the film 3 when the pack 1 is formed.

The frame 5, the folder means 4, the first and second sealers 8 and 10are schematically described, being well known to those in the trade.

In addition, the machine 100 comprises the above-mentioned film 3 feedmeans 14, positioned close to the frame 5, and designed to allow film 3feed in the same direction as the direction of feed A, when the productgroups 2 move close to the sealed front edges 7 of the film 3, and so asto maintain a fixed distance D between the sealed front edges 7 and therespective front end 2 a of the product groups 2 fed forward.

In more detail, these feed means 14 are positioned between the frame 5and the first sealing means 8, forming a stretch of the frame 5.

Structurally, these feed means 14 are evenly distributed around thechannel 6 formed by the frame 5 and they form the final stretch of theframe 5.

More precisely, as shown in FIGS. 9 to 11, the feed means comprise aplurality of film 3 feed belts 14, positioned around the frame 5,forming the final stretch of the frame 5 so that they at least partlycomplete the channel 6 along all of its sides.

The group of belts 14 comprises: a first set 15 of upper belts and asecond set 16 of lower belts opposite one another and present in equalnumbers; a third and fourth set 17, 18 of lateral belts 14 opposite oneanother and present in equal numbers.

Each belt 14 of the first and second sets 15, 16 can preferably bepositioned coplanar with the extension of the frame 5.

Similarly, each belt 14 of the third and fourth sets 17 and 18 can bepositioned coplanar with the extension of the frame 5.

However, each belt 14 of the third and fourth sets 17 and 18 canpreferably be positioned at an angle to the extension of the frame 5,that is to say, projecting into the channel 6, and its position can beadjusted according to the contact with the film 3 and the product groups2 fed forward (as described below and illustrated in FIG. 12).

In terms of the construction architecture, each belt 14 of the four setspresent is closed in a loop on a respective shaped support 20 designedto allow the formation of an active branch 14 a for making contact withand feeding the film 3 simultaneously with the feeding of the productgroups 2.

Each support 20 is associated with a supporting base 21 shared by eachof the first, second, third and fourth sets 15, 16, 17, 18 of belts 14in order to maintain a stable fixed point for each set of belts 14present.

Each of the shaped supports 20 has a first pair of wheels 22 and 22 awhich rotate idly (forming the active branch 14 a) on which the belt 14runs around the shaped support 20, and a second wheel 23 keyed on atransmission and supporting shaft 24, transversal to each shaped support20, and shared by each of the sets 15, 16, 17, 18 of belts 14.

For movement of the belts 14 of each set, each of the belts 14 mayrotate idly about the shaped support 20 and may be moved by means ofpressure on the film 3 when the product groups 2 pass.

Preferably, although without limiting the scope of the invention, atleast the first and second sets 15 and 16, upper and lower, may bemotor-driven, by a single drive unit 25 connected to a kinematic motiontransmission system 26 positioned at the ends of the respectivetransmission and supporting shafts 24.

Similarly, the third and fourth sets 17 and 18 of belts 14 may bemotor-driven by corresponding independent drive units 17 m and 18 m.

Returning to the first set 15 of upper belts 14, the latter, partlyoverhanging the channel 6, are subject to an actuator 27, positionedabove the channel 6, and acting vertically on the shaped supports 20 soas to maintain a predetermined pressure on the feed belts 14 and toallow them to constantly adhere to the film 3 and the product groups 2passing (see arrow F27 in FIG. 9).

In addition, there are damper means 28 (for example springs), actingbetween the actuator 27 and the shaped supports 20, to allow bothconstant adjustment of the contact between the belts 14 and the film 3in contact with the product groups 2, and movement of the belts 14 awayfrom the film 3 upon the release of the pressure applied by the actuator27 simultaneously with sealing of the rear edges 11 of the pack 1 (seearrow F28 in FIG. 10).

As regards the third and fourth sets 17 and 18 of lateral belts 14, eachof these sets 17 and 18 may preferably but without limiting the scope ofthe invention, comprise a pair of belts 14 b and 14 c, slidablyconnected, with the support 20, to a vertical guide 29 (see also FIG.12).

By means of a rod 30, each upper belt 14 b is integral with the firstset 15 of upper belts 14 so as to maintain a constant distance from thefirst set 15 of belts 14 according to a vertical movement of the firstset 15 of belts 14. The adjustment is necessary in known changeoverprocedures in which the entire channel 6 must be adapted for the newconfiguration.

Similarly, the third and fourth sets 17 and 18 of belts 14 arecontrolled by a cylinder 31, acting perpendicularly on the correspondingvertical guide 29 to obtain a variation of the position of the sets 17and 18 of belts 14, moving them towards or away from one another (seearrow F31 in FIG. 11), depending on the configurations of the productgroups 2 being handled, and moving the film 3 away when the rear edges11 of a pack 1 are sealed, as already indicated regarding the first set15 of belts.

As indicated above, the angle of each of the third and fourth sets 17and 18 of lateral belts 14 can be adjusted using positioning means 19.

These means 19 (see FIG. 12) may comprise a curved slot 33 made in amobile portion 20 a of the shaped support 20 and concentric to thecenter of the second wheel 23 keyed on the motion transmission shaft 24:in this way it is possible to achieve predetermined angular positioningof the belts 14 irrespective of the position of the guide 29 and of thefixed part of the support 20 (see arrow F19 in FIG. 12).

A method and machine structured in this way therefore achieve the presetaims, thanks to the presence of the feed belts which form the finalstretch of the wrapping channel.

The belts allow the film to be fed simultaneously with the productgroups, keeping the latter away from the sealed front end during thestep for forming the rest of the wrapper until it is complete.

This procedure has two obvious advantages:

the first is that it eliminates the impact on the front end of the filmjust sealed and prevents it from being held taut for the entire time theproduct groups are fed forward, since in the conventional method thesealed front end is used to allow the film to exit the frame;

the second advantage, resulting from the first, is that the packagingprocess is speeded up, since it is not necessary to wait for thepost-sealing cooling time to elapse for the front of the film, which nowtakes place in a “masked” time, that is to say during the step in whichthe film and product groups are fed forward.

In this way the production cycle is faster than the conventional cycleand the end quality of the product (in terms of the seals) is definitelyhigher.

The invention described is suitable for obvious industrial applicationsand can be modified and adapted in several ways without therebydeparting from the scope of the inventive concept. Moreover, all detailsof the invention may be substituted by technically equivalent elements.

1. A bagging machine for producing a pack (1) for product groups (2);the machine (100) being of the type comprising at least: a frame (5)comprising folder means (4) designed to support a packaging film (3),which is wound around the folder means (4) and can be fed from a station(13); the frame (5) forming a channel (6) for the passage of the productgroups (2) fed forward by pusher means (9) in a direction of feed (A);first, transversal sealing means (8), positioned downstream of the frame(5), relative to the direction of feed (A), and designed to join,respectively, the front edges (7) of the packaging film (3), beforearrival of the product groups (2), and the rear edges (11) after theproduct groups (2) wrapped in the packaging film (3) have passed beyondthe first sealing means (8); second, longitudinal sealing means (10),positioned close to the frame (5) and designed to join two longitudinaledges of the film (3) when the pack (1) is formed, the machine (100)further comprising film (3) feed means (14) positioned close to theframe (5) and designed to allow film (3) feed in the same direction asthe direction of feed (A), when the product groups (2) move towards thesealed front edges (7) of the film (3), and maintaining a fixed distance(D) between the sealed front edges (7) and the front end (2 a) of theproduct groups (2) fed forward.
 2. The machine according to claim 1,wherein the feed means (14) are positioned between the frame (5) and thefirst sealing means (8), forming a stretch of the frame (5).
 3. Themachine according to claim 1, wherein the feed means (14) are positionedbetween the frame (5) and the first sealing means (8) and evenlydistributed around the channel (6) formed by the frame (5).
 4. Themachine according to claim 3, wherein the feed means (14) form a finalstretch of the frame (5).
 5. The machine according to claim 4, whereinthe feed means (14) comprise a plurality of film (3) feed belts (15),positioned around the frame (5), and forming the final stretch of theframe (5), at least partly completing the channel (6) along all of itssides.
 6. The machine according to claim 5, comprising a first set (15)of upper belts and a second set (16) of lower belts opposite one anotherand present in equal numbers.
 7. The machine according to claim 6,wherein each belt (14) of the first and second sets (15, 16) ispositioned coplanar with the extension of the frame (5).
 8. The machineaccording to claim 5, comprising a third set (17) and a fourth set (18)of lateral belts (14) opposite one another and present in equal numbers.9. The machine according to claim 8, wherein each belt (14) of the thirdand fourth sets (17, 18) is positioned coplanar with the extension ofthe frame (5).
 10. The machine according to claim 8, wherein each of thebelts (14) of the third and fourth sets (17, 18) is positioned at anangle to the extension of the frame (5), that is to say projecting intothe channel (6), and its position can be adjusted according to thecontact with the film (3) and the product groups (2) fed forward. 11.The machine according to claim 10, wherein each belt (14) is closed in aloop on a respective shaped support (20) designed to allow the formationof an active branch (14 a) for making contact with and feeding the film(3) simultaneously with the feeding of the product groups (2); eachsupport (20) being associated with a supporting base (21) shared by eachof the first, second, third and fourth sets (15, 16, 17, 18) of belts(14).
 12. The machine according to claim 11, wherein each shaped support(20) has at least a first pair of idle wheels (22, 22 a) on which thebelt (14) runs around the shaped support (20), and a second wheel (23)keyed on a transmission and supporting shaft (24), transverse to eachshaped support (20), and shared by each set (15, 16, 17, 18) of belts(14).
 13. The machine according to claim 11, wherein each of the belts(14) may rotate idly along the shaped support (20) and may be moved bymeans of pressure on the film (3) when the product groups (2) pass. 14.The machine according to claim 12, wherein at least the first and secondsets (15, 16), upper and lower, are motor-driven, by a single drive unit(25) connected to a kinematic motion transmission system (26) positionedat the ends of the respective transmission and supporting shafts (24).15. The machine according to claim 12, wherein the third and fourth sets(17, 18) of belts (14) are motor-driven by corresponding independentdrive units (17 m, 18 m).
 16. The machine according to claim 11, whereinat least the first set (15) of upper belts (14) is subject to anactuator (27), positioned above the channel (6), acting vertically oneach shaped support (20) and designed to apply a pressure on the feedbelts (14) to allow them to constantly adhere to the film (3) and theproduct groups (2) passing; there being damper means (28) acting betweenthe actuator (27) and the shaped supports (20), to allow both constantadjustment of the contact between the belts (14) and the film (3) incontact with the product groups (2), and movement of the belts (14) awayfrom the film (3) upon the release of the pressure applied by theactuator (27) simultaneously with sealing of the rear edges (11) of apack (1).
 17. The machine according to claim 12, wherein each of thethird and fourth sets (17, 18) of belts (14) comprises a pair of belts(14 b, 14 c) connected, with the support (20), to a vertical guide (29);each upper belt (14 b) being integral, by means of a rod (30), with thefirst set (15) of upper belts (14) so as to maintain a constant distancefrom the first set (15) of belts (14) according to a vertical movementof the first set (15) of belts (14).
 18. The machine according to claim17, wherein the third and fourth sets (17, 18) of belts (14) arecontrolled by a cylinder (31), acting perpendicularly on thecorresponding vertical guide (29) to obtain a variation of the positionof the sets of belts, moving them towards or away from one another,depending on the configurations of the product groups (2), and movingthe film (3) away when the rear edges (11) of a pack (1) are sealed. 19.The machine according to claim 17, wherein each of the third and fourthsets (17, 18) of lateral belts (14) has positioning means (19) for theangle of inclination of each belt (14); each of the positioning means(19) comprising at least a curved slot (33) made in a mobile portion (20a) of the shaped support (20), allowing predetermined angularpositioning of the belts (14).